20 million

Metric tons of greenhouse-gas emissions that Walmart plans to eliminate from its global supply chain by the end of 2015. The world's largest retailer collaborated with the Environmental Defense Fund on this effort, which places a significant burden on suppliers.

Suppliers to the 4,300 Walmart stores and Sam's Clubs in the U.S. are already being called on to use less packaging—you might have noticed the new recyclable DVD cases. The suppliers are also encouraged to seek out local sources wherever possible. "The approach is not telling suppliers that they have to change their distribution system," said Elizabeth Sturcken, the EDF's managing director of corporate partnerships, in a roundtable discussion of the plan. "Instead, it's looking at new approaches for carbon pollution cuts. If that means pursuing suppliers with local sources, that idea is being deeply embedded in this company."

—Daniel DiClerico

Essential information: You can reduce your carbon footprint by using less energy at home and replacing energy-hog appliances with higher-efficiency models using a cash for clunkers for appliances rebate. Note that our safety videos on bicycle helmets, carbon-monoxide alarms, sunscreen, and other subjects are being screened at Walmart, Costco, and other retailers.